And for those of you doing it, remember to spell 'Eyjafjallajokull' correctly.
Not very confident tbh, good luck to all.
Boxing Day Tsunami 2004
At highest, wave was 15m high
Affected Indonesia first then Thailand and eventually India etc.
I hope that helps.
Just get to work now and try to answer some case study questions to ingrain it before tomorrow. Don't try and memorise it.
I typed up some notes today on all of the natural hazards, here they are - they're quite basic but this exam isn't hugely demanding:
Geography OCR B – SDME Notes
§ Causes of volcanoes:
§ Volcanoes are formed at convergent boundaries (subduction zones) and divergent boundaries.
§ At convergent boundaries, low density basalt which forms oceanic crust is pressed beneath a more dense continental crust. This causes the oceanic crust to melt, and it often ascends through the continental plate and forms volcanic eruptions.
§ At divergent boundaries, two plates are moving away from each other. The block between the two faults drops into the mantle. This forms a steep central valley known as a rift, which magma seeps upwards and fills. Volcanoes and islands form when the magma reaches the surface and cools.
§ Types of volcanoes:
§ There are two main types of volcanoes: shield volcanoes, strato-volcanoes and hot-spot volcanoes.
§ Shield volcanoes are formed at divergent (constructive) plate boundaries. They tend to be low and wide due to the low viscosity of the escaping magma which distributes it over a wide location. Eruptions of shield volcanoes are much gentler and can last many months.
§ Strato-volcanoes (cone volcanoes) are formed at convergent plate boundaries which have subduction zones. When magma escapes, it reacts with carbon dioxide and water which causes it to become much more viscous than shield volcanoes – resulting in less widespread distribution and a cone-shape. The eruptions are extremely violent and they release huge amounts of pumice alongside pyroclastic flows and clouds of ash (nuées).
§ Hot-spot volcanoes occur at plate boundaries in which the crust is very thin. Chains of volcanic islands form and cool quickly due to the presence of water. They tend to be shield volcanoes and are similarly less destructive.
§ Effects of volcanoes:
§ Lahars – a quick flow of mud and water which has been heated by the lava.
§ Pyroclastic flow – a wave of extremely hot gas protruding from the volcano.
§ Tsunamis – volcanoes near the water can collapse and cause tsunamis.
§ Lava flow – can destroy homes while covering farmland and roads.
§ Nuées – clouds of ash which can affect air quality and engine function.
§ Boulders – can be chucked out of the volcano which can destroy infrastructure.
§ Uses of volcanoes:
§ Mineral deposits – volcanoes are often associated with diamond, copper, silver, gold and zinc mines.
§ Tourism – volcanoes are very appealing to the tourist industry.
§ Fertile soils – the deposition of minerals causes fertile soil which is invaluable to the agricultural industry.
§ Geothermal power – power generating companies are often situated here in order to access renewable energy.
§ Volcano case studies:
§ Nevado del Ruiz (1985) – Main threat was lahars which cut off roads and transport networks, making rescue effort difficult. Evacuations were initially ordered but dismissed due to ineffective measuring equipment.
§ Mount Etna (2002) – Lava movement was the main effect which threatened valuable industry. Response was quick and efficient.
§ Causes of earthquakes:
§ Earthquakes occur at all plate boundaries (divergent, convergent and transform). The focus is the precise location at which the earthquake occurs – which is often below the surface. This is transposed directly up onto the surface and is designated as the epicentre.
§ Earthquakes occur as a result of convection currents within the mantle. Heat from radioactive decay within the Earth causes sections of the mantle to circulate while transferring heat energy. This has an effect on the crust which results in movement. When movement is prevented by colliding plates, large forces build up which when released cause earthquakes.
§ Effects of earthquakes:
§ Destruction of infrastructure – buildings which aren’t able to move or release stress can be destroyed.
§ Landslides – shaking of the ground can cause landslides which may disrupt roads and railways.
§ Tsunamis – subterranean earthquakes can cause tsunamis and coastal flooding.
§ Liquefaction – earthquakes may cause groundwater to rise and flood non-urbanised areas.
§ Transport disruption – earthquakes can cause infrastructure such as motorways to collapse, which prevents transportation from being effectively distributed.
§ Factors affecting the damage of an earthquake:
§ Distance from epicentre – the further away from the earthquake, the lesser the damage.
§ Geology – weak rock or sediment results in greater damage.
§ Design of buildings – rigid structures are poor at relieving stress generated by earthquakes; flexible buildings are more likely to withstand the shockwaves.
§ Earthquake case studies:
§ Northridge, California (1994) – Freeway collapsed which prevented aid from entering the city effectively. Hazards caused by broken gas pipes, unsecure appliances such as water boilers and concrete buildings were severely affected.
§ Sichuan, China (2008) – Highlighted the construction flaws of schools in which many collapsed. Poor quality houses were a major factor in amplifying the damage.
§ Tropical storms:
§ Causes of tropical storms:
§ Tropical storms are caused by large depressions which form over tropical oceans. They require a minimum temperature of 27°C and a 60m depth to form. Fast-rising warm air creates an area of very low pressure, which sucks in air and the rotating winds cause moisture to be absorbed.
§ A depression becomes a tropical storm when wind speeds exceed 74 mph, and when they are typically 700 km in diameter or 13 km in height.
§ These conditions are only satisfied in the areas around the equator in the tropics – such as North America / Central America, Caribbean, Africa, South Asia and Australia.
§ Types of tropical storms:
§ Cyclone – a system of winds rotating inwards to an area of low pressure.
§ Hurricane – a violent tropical storm in the Caribbean region.
§ Typhoon – a violent tropical storm over the Indian and Pacific oceans.
§ Effects of tropical storms:
§ Storm surges – downward pressure exerted by the tropical storm causes the sea level to rise slightly in local areas, causing coastal flooding.
§ Strong winds – these cause the destruction of infrastructure and local habitats.
§ Fish / birds – migration patterns and distribution can be temporarily or permanently disrupted.
§ Tropical storm case studies:
§ Hurricane Katrina (2005) – Mass flooding in New Orleans occurred due to the ineffective defences which were breached. There were notably no warnings issued in the long-term, but shelters were set up shortly after the warnings intensified.
§ Cyclone Nargis (2008) – The effectiveness of the response teams from other countries was limited by the military government who refused international aid.
§ Causes of droughts:
§ Droughts occur when there is a lower than average amount of rainfall in a given time period.
§ The low rainfall is often caused by rising air which carries water molecules away, which prevents precipitation from occurring.
§ Factors affecting the severity of droughts:
§ Climate – areas of low rainfall are more susceptible to drought.
§ Politics – war can affect access to water.
§ Technology – levels of technology dictate the efficiency of water storage and transportation.
§ Environment – different geology allows variation in water storage and runoff.
§ Use and users – in MEDCs, water is used for luxury rather than in LEDCs where it is used for subsistence.
§ Social – the number of people and demand affects the severity.
§ Economics – high wealth usually results in better capability to cope with drought.
§ Drought case studies:
§ Ethiopia in the Sahel (1984-85 / 2006) – 85% of the population relied on rainfall for farming for a living. The civil war conflict caused negligence towards the drought issues.
§ Australia (2005-6) – Meteorological events called El Niño combined with disruption caused the drought. It led to water rationing / hosepipe bans throughout Australia.
me neither , i wish i could re-wind back time and straighten out my revision materials so now these past days i would have only needed to go through them without much hassle. guess i will not be sleeping tonight; besides i stayed up so late yesterday by lunch i could barely stay awake guess i will need to make a note to buy red bull before going to school xD